Re: ATM issue: one Host Four Nodes

On Fri, 6 Sep 2002,  wrote:


Well, if you have 2 PHYs per node you can set up the ring as you've drawn
it - i.e. with each ATM node connected by one PHY to the previous node,
and by the other PHY to the next node.  Alternatively, if you only have
one PHY per node, you can put a switch in the middle and have the host and
each node connected to the switch.

The other solution (I've just realised this) is to use an OC3 PHY.  With
this physical medium you can seperate RX and TX streams.  I suppose that
was what you were suggesting in the first place.

Alex

Hi Alex£¬
you mean that maybe i need an ATM switch to creat the ring topology
how can i implement it? can you give more detail info on it?
Regards
Li
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quoted

From:Alex Zeffertt [off-list ref]
Reply-To:
To: <redacted>
Subject: Re: ATM issue: one Host Four Nodes

On Thu, 5 Sep 2002,  wrote:


In each NODE set up 1 terminated VC, and 3 switched VCs (using the
atm-860.o specific /proc/net/atm/switch interface).

here's an example of how to set up a switched VC from 0.0.32 to 0.0.32
using the atm-860.o driver:

echo add 0.0.32 0.0.32 1000 cbr > /proc/net/atm/switch

          ^      ^     ^    ^
        from-VC to-VC  PCR  TT

See http://mpc860sar.sourceforge.net for the source code.

Alex

BTW:  If you're board only has one PHY then you need an ATM switch in the
middle to create the ring topology.  If it's multi PHY then you will need
to modify the atm-860.o driver because it doesn't support this yet.  (I
think that multi-PHY is only available on MPC862s anyway....)

quoted

Hi all,
We just have such a system to build.
                                ________
                                |      |
                            RX  | ATM  |_TX____________________________
  |---------------------------->| HOST |                              |
  |                             |      |                              |
  |                             |______|                              |
  |                                                                   |
  |      ________       ________        ________       ________       |
  |      |      |       |      |        |      |       |      |       |
  |   TX | ATM  | RX  TX| ATM  | RX   TX| ATM  | RX  TX| ATM  |  RX   |
  |------| NODE |<------| NODE |<-------| NODE |<------| NODE |<------|
         |      |       |      |        |      |       |      |
         |______|       |______|        |______|       |______|
             A              B               C              D
It's used to perform high speed data acqusition.
ATM HOST -- a pc with an ATM card
ATM NODE -- MPC860 with linux-2.4.4

The ATM HOST is responisble for sending controlling information to ATM NODEs
and receiving data from each NODEs.
The ATM NODE is responsible for performing data acqusition.

As the diagram show,ATM NODEs are connected one after another.
we use one VPI/VCI to identify one ATM NODE, so if the ATM HOST send the
control message to ATM NODE D, the message will touch  ATM NODE A¡¢B¡¢C first,
then ATM NODE D. In order to improve the system capacity and efficiency,
the ATM NODE A¡¢B¡¢C should ignore this message(not parse it) and send it
to the next node, in another words, this message should be bypassed in low
level(e.g. PHY level) by ATM NODE A¡¢B¡¢C. How can i get this point?
Any advice will be greatly appreciated!
Best Regards!
Li

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